Follower control for traveling receptacle



July 27, 1965 H. G. FRosTlcK ,5

FOLLOWER CONTROL FOR TRAVELING RECEPTACLE Filed March 4, 1965 2 Sheets-Sheet l E1rs= 1 I/VVENTOR HAROLD 6. E9037 CK J Afro/nay July 27, 1965 os c 3,196,500

FOLLOWER CONTROL FOR TRAVELING RECEPTACLE Filed March 4, 1963 2 Sheets-Sheet 2 I/VVE/VTOR HAROLD 6. FROST/CK Attorney United States Patent 3,196,500 FOLLOWER CONTROL FOR TRAVELING RECEPTACLE Harold G. Frostick, North Palos Township, Cook County,

Ill., assignor to United States Steel Corporation, a corporation of New Jersey Filed Mar. 4, 1963, Ser. No. 262,784 7 Claims. (Cl. 2257.2)

This invention relates to a follower control for an electric-motor driven receptacle, with particular reference to a follower control for a traveling receptacle for removing high temperature workpieces from a continuous metal casting unit and the like.

In the continuous casting of metals, processes are employed whereby metal product emerges vertically downw-ardly in a continuous workpiece which is desirably severed into lengths for convenience in handling and further processing. These sections, which may be of considerable mass, such as those known as slabs, are individually lowered out of the way of oncoming product, to astation for transfer to other handling means. During the aforementioned lowering process, the generally vertical attitude of the pieces is maintained, and the traveling receptacle with which this invention is concerned provides support for the lower ends thereof, to insure a regulated rate of descent.

To accomplish its purpose in conjunction with the aforementioned continuous casting operation, the receptacle must be in position, proximate to the lower end of the emerging product, at the time of its severance from the main body; lower the severed section out of the interfering range of newly emerging product; and return to a position for acceptance of the next severed section prior to its cut-off.

In the case of cast products emerging at relatively high temperatures, such as steel near its melting point, it has been found important to maintain an air gap between the product and the receptacle proper, during the period the receptacle is in position below the end of the product awaiting its severance, to avoid premature disintegration of the receptacle bottom members by the heat evolved from the newly cast product.

It is an object of the invention to provide a follower control for a receptacle for the aforementioned purpose, and the like, which maintains the receptacle in register with the moving end of a continuously formed product,

and the like, which may be emerging with varying speed, A

and even direction.

It is a further object to provide, for handling high temperature workpieces, a receptacle follower control as aforementioned which self-spaces the receptacle proper in relation to the unsevered product, to provide an insulating air gap therebetween to retard thermal disintegration of the receptacle.

Also, it is an object of the invention to provide, in conjunction with said follower control, a self-acting control means for initiating and controlling downward movement of the receptacle upon product severance, and for initiating and controlling its return travel to produce acceptance position after the product has been transferred therefrom.

These and other objects will become more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is a plan view of a traveling receptacle installation with follower control means of the invention incorporated therein;

FIGURE 2 is a side elevational view of the apparatus shown in FIGURE 1;

FIGURE 3 is a perspective view of a receptacle with 3,196,500 Patented July 27, 1965 "ice position sensing and other control members installed therein;

FIGURE 4 is a view taken along the line IVIV of FIGURE 1, to detail a sensing member installation; and

FIGURE 5 is an electrical schematic of control circuitry.

Referring particularly to FIGURES 1 and 2, which depict the overall setting of a typical receptacle installation of the invention as applied to the continuous casting or" steel slabs, a portion of a downwardly emerging slab 1 is shown in dot and dash lines in entry relationship to receptacle 2. The receptacle receives support from vertical side guide members 3 and is raised and lowered by means of a wire rope 4 passing over sheaves 5 to drums 6, which are driven by electric motor 7 through drive mechanism 8.

In the receptacle embodiment shown in enlarged scale in FIGURE 3, slab 1 is again shown in position of entry into the receptacle, where, upon severance of a section thereof for lowering away from the continuous casting, it receives upward support from fixed fingers 10. A movable finger 11, which is an arm rigidly attached to rockshaft 12, is representative of means for sensing the closing distance between support fingers 10 and the slab product. Movable finger 11 has a movement range depicted by the dotted line representations of FIGURE 4, and in the absence of being actuated downwardly by product proximity, the finger raises by virtue of the urging of torsion spring 13, until projection 14, rotating with rockshaft 12, engages stationary stop 15.

Rockshaft 12 motion drives reversible multi-contact cam limit switch 20 through motion multiplication means represented by gearbox 21. A limit switch such as illustrated and described in Westinghouse Electric Corporation price list 15-321, page 2, effective May 10, 1961, has been successfully employed.

Multiple contact switch 20 contains opening and closing contact-s 20a, 20b, etc. which are schematically presented in FIGURE 5 in conjunction with the circuitry operated thereby, which includes means for varying the speed and direction of motor 7, shown in receptacle driving relationship through drum 6 and wire rope 4.

Motor 7 receives current from direct current generator 22, the output voltage and polarity of which are responsive to the output of exciter 23 which latter output is responsive to its field supply 24, which is variable in voltage and polarity by action of switch 20 upon the intervening circuitry, as shown in FIGURE 5 and as will be more fully described below.

By way of more specific description of certain aspects of motor control operation consideration may be given to the situation where the receptacle 2 is empty, in which case sensing finger 11 will be in its uppermost position. For this position of the sensing means contacts 20a, 20b, and 20c are closed and contacts 20d, Ztle, and 20 are open as depicted in FIGURE 5, permitting full current 24 being supplied to the field of exciter 23, with the polarity as indicated, which leads to motor operation with such speed and direction as to cause relatively high speed upward travel of the receptacle.

Upon the approach of receptacle 2 and slab product 1, to predetermined spacing therebetween, sensing finger 11 is actuated by slab contact to partial depression, which in turn actuates cam limit switch20 which is aligned to open contact 200 whereby resistance 25 is introduced into the exciter current source 24 with resultant reduction in exciter field current and consequent reduction in generator output, motor speed, and receptacle speed. Upon further partial depression of the sensing finger all contacts predeterminately open to stop receptacle movement.

Similarly, upon further approach of slab 1 and recep tacle 2, but short of slab contact with fixed receptacle m '3 fingers 19, at predetermined depression of sensing finger 11, only contacts 20d and 20 e are closed, resulting in reversal of exciter 23 field polarity and downward receptacle movement. Since resistance 26 is in the circuit, this motion is at predetermined'relatively low speed.

Upon full depression of sensing finger 11, as caused to product proximity sensing means, and by use of suitable j current supply 24 and resistances, at least one of which is preferably variable, as represented by resistance 26, 'desired high and low receptacle speeds, requirements, may be obtained, a

The choice of operating speeds for, receptacle travel,

in the continuous casting applicationin conjunction with to meet operating f position awaiting receipt of the severed product, said sensingandcontrol means being additionally so aligned that product severance andv bottoming thereof in the receptacle initiates downward travel of the receptacle to remove the severed product,

2. In a traveling receptacle installation driven by an electricmotor, for lowering the severed product of a vertically downwardly delivering continuous metal casting unit and thellike, means for follower control of the receptacle in relation, to emergent product comprising self-acting means forr'naintaining an air gap between said receptacle andtthelower end of, product prior to severwhich the follower control of the invention has been I considerations. V a o vi DownwardQreceptacle speed upon product severance must be sufficient to remove the severedsection from interference with oncoming'product. "Moreover, the return receptacle speed, together with that of lowering,must be sufficient, to permit the receptacle to arrive near the principally described, depends largely upon the following lower end ofthe emerging casting in time to receive the next severed workpiece.

The low speeds of receptacle travel are chosen by alternate upward and downward receptacle movement, in a hunting manner, the receptacle is enabled to follow themovements of the lower end of the unsevered product, when the latter is moving at usual'speeds. Since the sensing means are set tooperate with predetermined closing distance betweenthe unsevered product and the support fingersof the receptacle, the is maintained. a v p It, may be noted that although operating contingencies sometimes require upward movement of uncutcasting, or

rapid alternate upward and downward movement thereof,

the follower control ofthe invention insures continued receptacle presence, in position awaiting product cut-off. In the circumstance where speed of movement of the so that desired insulating air gap ance, for initiating and controlling the speed of downward movementof the receptacle upon product severance, and for initiating and controlling the speed of its return to product receipt position after the product has been transferred therefrom, said'mean's' comprising means carried 1 by the receptacle for sensing -the de'gree of proximity of unsevered product, the introduction'of se'veredproduct into the receptacle,- and the emptying of the receptacle, and means responsive to'said sensing means for control of the. direction'and speed of said motor, which determines receptacle travel, said control means including means for control .of the voltage and polarity of a direct current and .comprising .multi-speed: regulator V circuitry for both upward and downward receptacle travel, said sensing and control means being so aligned that, with the sensing means beyond theinfiuence of the product, the receptacle travels upwardly at relatively high speed until upon its arrival at predetermined spacing from the end of the unsevered product the sensing means are actuated to cause upward travel at relatively lowspeed and upon predetermined reduction in spacing the sensing means are further actuated to cause downward receptacle travel at relativelylow speed," and upon product severance the sensing means are actuated to cause downward travel at from the receptacle.

unsevered product exceeds the normal speeds for which the'low speed of receptacle travel was advantageous, the sensing means automaticallybring into operation the high speed range V of receptacle travel for non-interrupted follower action.

Termination of receptacle travel at the lower end of its path, at its unloading position, may be by conventional limit switch means. i t I do not desire to be limited to the exact'details of construction, and applications, shown and described, for

obvious modifications will occur to a person skilled in the art. a

I claim: a V

1. In a traveling receptacle installation driven by an 3. The, combination of claim 2 comprising a direct current generator with exciter,"as current source for said motor, the output j of said exciter being responsively controlled by said means for control of the voltage. and polarity of a direct current; l 4. The combination of claim 2 in which said means for control of the voltage and polarity of a direct current comprise circuitsjcontaining resistances and polarity varying means, whereby upon appropriate circuit selection the voltage and polarity of said current may be predeterminately varied, and means for selecting said circuits responsivelyconnected to said sensing means. 1 V v 5. The combination of claim 4 in which said means for selecting said circuits comprise a reversible multiple con- I tact cam limit switch responsively connected to said senselectric motor, for lowering the severed'product of a 7 ing unit and thelike,-means, for follower control of the receptacle in relation to emergent product comprising vertically downwardly delivering continuous metal castmeans for self-spacing said receptacle relative. to the lower end of unsevered product including means carried by the receptacle for sensing the degreetof proximity of said unsevered product, when in the near vicinity thereof, and means responsive to said sensing means for controlof the direction and speed of said motor, said sensing and con-' trol means being so aligned that the unloadedreceptacle travels upwardly until the sensingmeans are actuated at a predetermined spacing between receptacle and unsevered product, to reverse the direction of receptacle, travel to a downward direction, which approach and reversal isrepeated. until product severance, whereby a protective air a gap is maintained between the-receptacle proper and the emerging product duringrthe period the receptacle is in ing means,

6. The combination ofclaim comprising sensing means including a rockshaft mounted in said receptacle,

a rocker arm rigidly attached thereto which projects into the receptacle in such position as to vbe responsively actuated by product proximity, means'responsively connecting thesensing means and said cam-limit switch comprising means for rockshaft motion multiplication, and means for self-return of said arm to a p'ositionto sense entry or removal of said product. i r

7. Ina downwardly delivering continuous metal casting unit'wherein the emergingworkpiece is severed into sec tions and the sections-are individually lowered out of the wayof oncominglproduct by a traveling receptacle adapt- 'ed to support the sections vertically at their lower ends,

the combination with the receptacle of reversible variable speed electric-motor actuated drive means having associated follower control means, saidcontrol means com,- prising position sensing m'eans being progressively and reversibly responsive to variations in mutual proximity of workpiece and receptacle within a zone between bottoming of the workpiece in the receptacle and separation of workpiece and receptacle bottom by a distance to provide a heat insulating air gap therebetween, circuit means for reversing and varying the speed of said motor, and elec trical switching means operatively connected with said sensing means and said motor circuit means, the operative alignment of said sensing, switching, and circuit means being such that, with separation of receptacle and emerging unsevered workpiece by greater than said air-gap distance, motor operates to cause relatively high speed up- Ward travel of the receptacle, to meet emerging workpiece prior to its severance, upon approaching air gap distance said sensing means are initially actuated with resultant motor speed reduction, upon continued approach of receptacle and workpiece the motor stops, upon further approach of receptacle and workpiece motor reverses at reduced speed, said reduced motor speeds being adapted to provide alternate upward and downward receptacle movement, in a hunting manner, prior to workpiece severance, with maintenance of the receptacle in register with the lower end of the emerging workpiece while maintaining an air gap therebetween, and, upon severance of a section of the workpiece and resultant bottoming thereof in said receptacle, the sensing means activates motor means for relatively high speed receptacle descent to remove the severed section from interference with emerging workpiece and to permit timely receptacle return to register position to await the next severed section.

References Cited by the Examiner UNITED STATES PATENTS WILLIAM J. STEPHENSON, Primary Examiner.

MARCUS U. LYONS, Examiner. 

1. IN AS TRAVELING RECEPTACLE INSTALLATION DRIVEN BY AN ELECTRIC MOTOR, FOR LOWERING THE SEVERED PRODUCT OF A VERTICALLY DOWNWARDLY DELIVERING CONTINUOUS METAL CASTING UNIT AND THE LIKE, MEANS FOLLOWER CONTROL OF THE RECEPTACLE IN RELATION TO EMERGENT PRODUCT COMPRISING MEANS FOR SELF-SPACING SAID RECEPTACLE RELATIVE TO THE LOWER END OF UNSEVERED PRODUCT INCLUDING MEANS CARRIED BY THE RECEPTACLE FOR SENSING THE DEGREE OF PROXIMITY OF SAID UNSEVERED PRODUCT, WHEN IN THE NEAR VICINITY THEREOF, AND MEANS RESPONSIVE TO SAID SENSING MEANS FOR CONTROL OF THE DIRECTION AND SPEED OF SAID MOTOR, SAID SENSING AND CONTROL MEANS BEING SO ALIGNED THAT THE UNLOADED RECEPTACLE TRAVELS UPWARDLY UNTIL THE SENSING MEANS ARE ACTUATED AT A PREDETERMINED SPACING BETWEEN RECEPTACLE AND UNSEVERED PRODUCT, TO REVERSE THE DIRECTION OF RECEPTACLE TRAVEL TO A DOWNWARD DIRECTION, WHICH APPROACH AND REVERSAL IS RE- 